Cannot modify Max Speed on Client side only

I cannot increase max walk speed on client. It can only be done on the server. I have a video showing how the setup for this is fine. I’m losing my mind trying to figure out why I cannot run/increase max walk speed while holding shift on the client while it works perfectly fine on the server.
Blueprint replicated? - Check
Variables replicated? - Check
Gamemode changed? - Check

I don’t get it!!!

Video Description Here